KellenVancouver
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Martin started a thread about the recent resurgence in cassette tapes, which stimulated a small sidebar about 78 vinyls. I’m not a vinyl person, but I grew up with them (LPs and 45s, not 78s!) and I got to wondering how they developed as a medium. Plus, I’ve always been curious about why 45 records had the big hole compared to LP records with the little hole. So did some online research and came up with the following which I’m sharing in case it piques interest for anyone else. As they say in England, “Mind the step” which is to say I did this kind of quickly so hopefully there is no incorrect information here, but if something needs correction please point it out and help us all with better knowledge.
When records were first popularized they operated at all range of speeds, from 60 RPM all the way up to 130 RPM. Speeds between 78 and 80 RPM were common by 1910. The big record manufacturer prior to WWI, Grammophone, established 78 RPM as its standard speed in 1912, but the official 78 RPM speed (technically, 78.26 RPM) was not standardized until 1925. This was done for manufacturing reasons, in conjunction with the National Association of Broadcasters, to accommodate the typical 3,600 RPM motor using a 46-tooth gear (3600 divided by 46 = 78.26).
Those older 78s were generally made of a shellac resin. That’s why you’ll sometimes hear 78s referred to as “shellac records.” When the country entered WWII, shellac supplies dwindled. That’s when the industry turned to making records with vinyl (which also had the advantage of not being as brittle as shellac).
The big downside of a 78 was that a typical 10-inch record could only play about four minutes of music, which was not enough for a symphony. To solve that problem, in 1931 Radio Corporation of America (RCA) introduced a new type of 12-inch record. Working with another big name at the time, Vitaphone, they matched that 12-inch record with another new innovation, “talkie” motion picture film. A reel of talkie film lasted 11 minutes. Using the standard 3600 RPM phonograph motor, they made a record that would match that same 11 minutes, and that is what gave birth to the rotational speed of the 33.33 RPM record.
Unfortunately for RCA, the Great Depression bombed sales of their 33 RPM records and players (record industry sales fell an incredible 95% from 1930 to 1931). People just stayed with their 78s and were not about to spend money on RCA's new fangled 33 RPM idea. Given the lack of sales, and perhaps showing a monumental lapse of judgment, RCA let their patents associated with the new 33 RPM record expire.
Meanwhile, Columbia Records took RCA’s 33 RPM technology and advanced it with vinyl records. Columbia managed to produce vinyl records with grooves much more closely spaced than on the old 78s, what came to be known as “microgrooves.” That more than doubled the maximum listening time on a 33 RPM record from 11 minutes to 24 minutes. Naturally, those improvements became popular with a public that was in a buying mood after WWII.
Poor RCA was really ticked about all this. Their own technology was being used against them. Because they let their patents expire, Columbia was killing them with 33 RPM vinyl records. To fight back, RCA came out with their own 7-inch diameter record that would spin at an entirely new speed, 45 RPM.
RCA didn’t select 45 RPM just to be different (and no, it has nothing to do with the equation 78-33=45). Instead, 45 RPM was selected to improve fidelity for a 7-inch record. The greatest fidelity in a record is toward the outside edge due to velocity as it spins; with a greater velocity, it can store information on a longer groove surface and thus have lower distortion. A seven-inch diameter record suffers from lower fidelity since it starts with less velocity than a 12-inch record. However, by increasing the speed 35% to 45 RPM, RCA gained a 35% increase in groove velocity and better sound. Of course the trade-off was the record could just play one song per side. That’s where the hole comes in.
RCA made the 7-inch record with a much bigger hole, 1.5 inches in diameter. That compared to the standard center hole diameter for a 33 (based on the sized used by 78s) of 9/32 inch. There were three primary reasons for that. First, RCA’s idea was that by stacking their 45 records on a six-inch tall by 1.5-inch diameter spindle they could achieve much greater overall listening time than the maximum 24 minutes attained by a 33 RPM record. A record player that automatically dropped the next record into place on the six-inch spindle (which was easier to accomplish with a wider diameter) could play up to 60 minutes of continuous music, more than double the time of a Columbia 33 RPM record.
Another reason was RCA wanted to be like today’s Apple, have a proprietary system that would force customers into buying their products. Lastly, there was a technical reason. Dropping a record spinning at 45 RPM onto a 9/32-inch spindle would quickly torque and distort the center hole, making it go out of round, thus introducing wobbliness into the spin of the record. Not good, so the larger diameter hole was the answer to maintaining a perfect spin longer. And that was especially important for a big industry at that time, jukeboxes. Jukeboxes could not afford to have records go out of round quickly, so the 45s with their larger, more stable hole became rather perfect (and ubiquitous) for jukeboxes.
When records were first popularized they operated at all range of speeds, from 60 RPM all the way up to 130 RPM. Speeds between 78 and 80 RPM were common by 1910. The big record manufacturer prior to WWI, Grammophone, established 78 RPM as its standard speed in 1912, but the official 78 RPM speed (technically, 78.26 RPM) was not standardized until 1925. This was done for manufacturing reasons, in conjunction with the National Association of Broadcasters, to accommodate the typical 3,600 RPM motor using a 46-tooth gear (3600 divided by 46 = 78.26).
Those older 78s were generally made of a shellac resin. That’s why you’ll sometimes hear 78s referred to as “shellac records.” When the country entered WWII, shellac supplies dwindled. That’s when the industry turned to making records with vinyl (which also had the advantage of not being as brittle as shellac).
The big downside of a 78 was that a typical 10-inch record could only play about four minutes of music, which was not enough for a symphony. To solve that problem, in 1931 Radio Corporation of America (RCA) introduced a new type of 12-inch record. Working with another big name at the time, Vitaphone, they matched that 12-inch record with another new innovation, “talkie” motion picture film. A reel of talkie film lasted 11 minutes. Using the standard 3600 RPM phonograph motor, they made a record that would match that same 11 minutes, and that is what gave birth to the rotational speed of the 33.33 RPM record.
Unfortunately for RCA, the Great Depression bombed sales of their 33 RPM records and players (record industry sales fell an incredible 95% from 1930 to 1931). People just stayed with their 78s and were not about to spend money on RCA's new fangled 33 RPM idea. Given the lack of sales, and perhaps showing a monumental lapse of judgment, RCA let their patents associated with the new 33 RPM record expire.
Meanwhile, Columbia Records took RCA’s 33 RPM technology and advanced it with vinyl records. Columbia managed to produce vinyl records with grooves much more closely spaced than on the old 78s, what came to be known as “microgrooves.” That more than doubled the maximum listening time on a 33 RPM record from 11 minutes to 24 minutes. Naturally, those improvements became popular with a public that was in a buying mood after WWII.
Poor RCA was really ticked about all this. Their own technology was being used against them. Because they let their patents expire, Columbia was killing them with 33 RPM vinyl records. To fight back, RCA came out with their own 7-inch diameter record that would spin at an entirely new speed, 45 RPM.
RCA didn’t select 45 RPM just to be different (and no, it has nothing to do with the equation 78-33=45). Instead, 45 RPM was selected to improve fidelity for a 7-inch record. The greatest fidelity in a record is toward the outside edge due to velocity as it spins; with a greater velocity, it can store information on a longer groove surface and thus have lower distortion. A seven-inch diameter record suffers from lower fidelity since it starts with less velocity than a 12-inch record. However, by increasing the speed 35% to 45 RPM, RCA gained a 35% increase in groove velocity and better sound. Of course the trade-off was the record could just play one song per side. That’s where the hole comes in.
RCA made the 7-inch record with a much bigger hole, 1.5 inches in diameter. That compared to the standard center hole diameter for a 33 (based on the sized used by 78s) of 9/32 inch. There were three primary reasons for that. First, RCA’s idea was that by stacking their 45 records on a six-inch tall by 1.5-inch diameter spindle they could achieve much greater overall listening time than the maximum 24 minutes attained by a 33 RPM record. A record player that automatically dropped the next record into place on the six-inch spindle (which was easier to accomplish with a wider diameter) could play up to 60 minutes of continuous music, more than double the time of a Columbia 33 RPM record.
Another reason was RCA wanted to be like today’s Apple, have a proprietary system that would force customers into buying their products. Lastly, there was a technical reason. Dropping a record spinning at 45 RPM onto a 9/32-inch spindle would quickly torque and distort the center hole, making it go out of round, thus introducing wobbliness into the spin of the record. Not good, so the larger diameter hole was the answer to maintaining a perfect spin longer. And that was especially important for a big industry at that time, jukeboxes. Jukeboxes could not afford to have records go out of round quickly, so the 45s with their larger, more stable hole became rather perfect (and ubiquitous) for jukeboxes.